In recent years there has been an ever increasing application of electronics circuits in equipment used in aggressive environments and high damage risk areas. This includes for example a wide variety of electronic navigation and communication equipment on ships and small boats, monitoring and analysis equipment in mines and factories, telecommunication equipment in outdoor locations, small computers in field and un-airconditioned environments. A frequent cause of failure of this equipment is related to water, water based solutions, salts and reactive gases coming into contact with the components of electronic circuits. When this occurs the damage can be either immediate (as in the case of salt solutions producing short circuits between components) or gradual (as in the case of corrosion attack on the metallic components).
Thus, it is desirable to provide some form of protection. Such protection may typically be in the form of a coating. The coating should preferably form a thin film on the components and thus minimize reductions in heat transfer from the components to the air. If heat transfer is not adequate the components may become overheated and fail. The coating should preferably be transparent so all components may be readily identified.
It is desirable that the coating dry rapidly so as to minimize any delay between coating and returning a circuit to service in field application, and to minimize production time in factory application.
The coating should preferably also dry to a hard, glossy film. A hard glossy film is desirable since it reduces the tendency of foreign particles, for example, dust, dirt and wind blown salt to adhere subsequently to the surface where they could cause damage through short circuiting or assisting corrosion.
The coating should preferably be readily removable so that soldering of the circuits is not prevented or impaired. When cured, the coating should preferably not have any tendency to spread over uncoated areas where the formation of an insulating layer could interfere with the operation of components.